nkthread(5)nkthread(5)NAMEnkthread - limits the number of threads allowed to run simultaneously
must be greater than
must be greater than
This may be set higher, but more will not be used.
Unless there are heavily threaded applications on the system, the
default formula is adequate if is tuned correctly.
The tunable controls the absolute number of threads allowed on a system
at any given time. Increasing it will allow more threads, and lowering
it will restrict the number of threads.
It can be determined that is too low when the message is seen in the
message buffer. The message can be read via or This message indicates
that an application was unable to create a thread. Setting too low can
cause application failures due to an inability to create new threads or
fork new processes.
It can be determined how many threads have been used simultaneously
prior to the above message by calling and examining the This field
indicates the "high water" mark of the number of threads that have been
Who Is Expected to Change This Tunable?
Anyone expecting to run large numbers of threads.
Restrictions on Changing
None. This tunable is dynamic.
When Should the Value of This Tunable Be Raised?
This value should be increased, either directly or as a result of tun‐
ing on most systems that are running many threads or processes.
What are the Side Effects of Raising the Value?
When Should the Value of This Tunable Be Lowered?
The value should be lowered only to limit the number of threads on the
system, or when there is memory pressure and the value of is far above
the expected usage.
What are the Side Effects of Lowering the Value?
Increased risk of application failure do to the inability to create new
threads or fork new processes.
What Other Tunable Values Should Be Changed at the Same Time?
All HP-UX kernel tunable parameters are release specific. This parame‐
ter may be removed or have its meaning changed in future releases of
Installation of optional kernel software, from HP or other vendors, may
cause changes to tunable parameter values. After installation, some
tunable parameters may no longer be at the default or recommended val‐
ues. For information about the effects of installation on tunable val‐
ues, consult the documentation for the kernel software being installed.
For information about optional kernel software that was factory
installed on your system, see at
was developed by HP.
SEE ALSOmax_thread_proc(5), nproc(5).
Tunable Kernel Parameters nkthread(5)